12.3 Passive Recovery of Coastal Dune Vegetation Following
Limitations to Human Trampling: A Case Study
from Central Italy
Here, we present a study aiming to assess the effects of limitations to human
trampling on dune vegetation in a protected coastal area of central Italy. Using a
diachronic approach (studying community changes over time), we compared
species cover and richness in a recently fenced sector (which strongly limits
trampling) with that of an open sector that has been subjected to trampling over the
course of a 4-year experiment. In other words, we have analyzed these two vegetation parameters over time (multitemporal analyses), searching for significant
quantitative changes during the study period. As previously mentioned, the detrimental impact of trampling has already been widely documented (see the above
references). Our main goal, therefore, was to assess whether species richness and
cover in remnant foredune habitats could recover with the aid of a fence as a
passive limitation to trampling and if so, try to estimate how long this recovery
process is likely to take. We focused on foredune habitats both because they are
likely to be exposed to the most trampling as visitors walk across the beach and the
surrounding dunes, and because the vegetation that distinguishes them is likely to
be the most susceptible to trampling. For the purposes of this study, we took
passive recovery to mean recovery without human support, except for the initial
act of erecting the fence.
12.3.1 Study Site and the Field Experiment
The experiment was conducted in the ‘‘Torre Flavia wetland’’ Natural Monument
(Latium region, central Italy; 41°58
0 N; 12°03
0 E), a small protected coastal reserve
(about 43 ha) located on the Tyrrhenian coast. Torre Flavia is a relic of a larger
wetland recently drained (Battisti 2006). This coastal dune sector is longitudinally
homogeneous and consists of a sandy beach with a row of degraded dunes and a
wetland dominated by Phragmites australis on the landward side (Fig. 12.2). The
degraded dunes are characterized by a narrow strip of strandline vegetation
dominated by Cakile maritima and Salsola kali (Habitat 1210 of the ‘‘Habitats
Directive’’—annual vegetation of drift lines) intermingled with embryo dune
vegetation dominated by Elymus farctus and Anthemis maritima (Habitat 2110—
embryonic shifting dunes). Continuing inland along the degraded dune, the presence of several diagnostic species of a mobile dune habitat (Habitat 2120—shifting
dunes along the shoreline) can be found (such as Eryngium maritimun and
Echinophora spinosa). However, the most characteristic species of this habitat,
Ammophila arenaria, is lacking. At the beginning of the experiment, even though
remnants of the three aforementioned habitats were present, they were heavily
190
A. T. R. Acosta et al.
Limitations to Human Trampling: A Case Study
from Central Italy
Here, we present a study aiming to assess the effects of limitations to human
trampling on dune vegetation in a protected coastal area of central Italy. Using a
diachronic approach (studying community changes over time), we compared
species cover and richness in a recently fenced sector (which strongly limits
trampling) with that of an open sector that has been subjected to trampling over the
course of a 4-year experiment. In other words, we have analyzed these two vegetation parameters over time (multitemporal analyses), searching for significant
quantitative changes during the study period. As previously mentioned, the detrimental impact of trampling has already been widely documented (see the above
references). Our main goal, therefore, was to assess whether species richness and
cover in remnant foredune habitats could recover with the aid of a fence as a
passive limitation to trampling and if so, try to estimate how long this recovery
process is likely to take. We focused on foredune habitats both because they are
likely to be exposed to the most trampling as visitors walk across the beach and the
surrounding dunes, and because the vegetation that distinguishes them is likely to
be the most susceptible to trampling. For the purposes of this study, we took
passive recovery to mean recovery without human support, except for the initial
act of erecting the fence.
12.3.1 Study Site and the Field Experiment
The experiment was conducted in the ‘‘Torre Flavia wetland’’ Natural Monument
(Latium region, central Italy; 41°58
0 N; 12°03
0 E), a small protected coastal reserve
(about 43 ha) located on the Tyrrhenian coast. Torre Flavia is a relic of a larger
wetland recently drained (Battisti 2006). This coastal dune sector is longitudinally
homogeneous and consists of a sandy beach with a row of degraded dunes and a
wetland dominated by Phragmites australis on the landward side (Fig. 12.2). The
degraded dunes are characterized by a narrow strip of strandline vegetation
dominated by Cakile maritima and Salsola kali (Habitat 1210 of the ‘‘Habitats
Directive’’—annual vegetation of drift lines) intermingled with embryo dune
vegetation dominated by Elymus farctus and Anthemis maritima (Habitat 2110—
embryonic shifting dunes). Continuing inland along the degraded dune, the presence of several diagnostic species of a mobile dune habitat (Habitat 2120—shifting
dunes along the shoreline) can be found (such as Eryngium maritimun and
Echinophora spinosa). However, the most characteristic species of this habitat,
Ammophila arenaria, is lacking. At the beginning of the experiment, even though
remnants of the three aforementioned habitats were present, they were heavily
190
A. T. R. Acosta et al.